1. Field of the Invention
The present invention relates to an image capturing device, image capturing method, and a storage medium having stored therein an image capturing program.
2. Related Art
Conventionally, as a method of correcting blur caused by hand movement for a digital camera, an electronic hand-blur correction method is known. In such a method, a plurality of images is consecutively captured and pixels corresponding to each of the images are added together. For example, by adopting a multiplane addition method in which multiple consecutive images captured at 60 frames per second for all pixels are processed by adding together, it is possible to acquire an image with an S/N (signal to noise) ratio several times better than that of a single image.
With regard to such an electronic hand-blur correction method using the multiplane addition method described above, effective hand-blur correction is performed if photography is carried out under conditions in which hand-blur correction is required, for example, in a state in which a certain level of blur caused by hand movement has occurred. However, a drawback is encountered in that hand-blur correction is still performed even under conditions in which photography does not require hand-blur correction, for example, in a state in which either no blur caused by hand motion or an extremely small level of blur caused by hand movement has occurred. In such a case, an unnecessary lowering of image quality may be caused due to the addition processing carried out, for example, by adding an image contaminated with noise to the other images, or in a state in which positions of the images are not properly aligned. In order to solve this problem, there is a method of performing the addition processing only in a case in which a certain condition is detected for which it is necessary to perform the hand-blur correction (see Japanese Patent Laid-open Application No. 2008-92005).
However, with regard to this method, whether to perform multiplane addition processing is determined by the digital camera before photography (such as when the shutter button is being half-pressed) based on whether the environment is one in which blur caused by hand movement is likely, for example, whether the environment in which photography is to be carried out is slightly dark or not. Therefore, conditions at the time of decision and at the time of actual photography (for example, when the shutter button is full-pressed) do not always match, resulting in an expected result of hand-blur correction not always being achieved.